This invention relates to percussion tools such as pneumatic hammers and hammer drills, and more particularly to a percussion tool incorporating an oil tank of the cartridge type by which the tool can be easily replenished with oil and which enables the user to readily ascertain the quantity of oil remaining in the tank.
Hammer drills for example for drilling concrete include a drill element adapted for rotation as well as for axial percussive oscillation by being repeatedly beaten on its inner end with a built-in hammer. Since the work is very hard, the hammer is reciprocated in repetition usually pneumatically by the combination of a piston and a cylinder. The sliding portion of the piston-and-cylinder means therefore requires a slight but continuous supply of oil.
For this purpose, conventional hammer drills have an oil reservoir provided in its main body for steadily lubricating the sliding portion. However, the operation of the hammer drill entails a considerable oil consumption, giving rise to the necessity of replenishing the oil reservoir relatively frequently. Use of a reservoir of increased capacity could lead to a less frequent replenishment, but the increased quantity of oil which must be wholly supported by the operator would burden the operator.
Hammer drills require due care during use against troubles such as the ingress of extreneous matter into the sliding or oscillating portion and wear on packings. Additionally the operator must check the tool for lubrication from time to time because when depleted of oil for one cause or another, the tool would be subject to serious troubles such as abnormal wear. Furthermore the oil applicator for lubricating the tool with its wick in contact with the crank for the piston is not always steadily serviceable over a prolonged period of time and requires frequent inspection for adjustment or repair. It is especially necessary that the interior of the reservoir be readily checkable for the quantity of oil to assure lubrication at all times.